Biomedical subjects

G Delling

Publications and source records attributed to G Delling.

At least 55 records · Page 3Linked to original sources

PubMed1999

[Computed assisted voice recognition. A dream or reality in the pathologist's routine work?].

During the last 30 years the analysis of human speech with powerful computers has taken great strides; therefore, cost-effective, comfortable solutions are now available for use in professional routine work. The advantages of using voice recognition are the creation of new documentation or archives, reduced personnel costs and, last but not least, independence in cases of unforeseen notification of illness or owing to annual leave. For voice recognition systems to be used easily, a considerable amount of time must be invested for the first 3 months. Younger colleagues in particular will be more motivated to dictate more precisely and more detailed because of the introduction of voice recognition. The effects on other sectors of medical training, quality control, histology report preparation, and transmission can only be speculated.

Artificial Intelligence↗

PubMed1999

[Gorham-Stout idiopathic osteolysis--a local osteoclastic hyperactivity?].

One rare case of so-called massive idiopathic osteolysis Gorham-Stout is presented. In a 77-year-old female patient the whole right femoral head and neck of femur was resorbed within 2.5 month following trauma. As a histologic cause for the osteolysis, a marked stimulation of osteoclasts on the spongiosa, especially intracortically, was observed. The course and the clinical findings are described, and the pathogenesis and treatment are discussed in comparison with the present literature. The results suggest that an early antiresorptive therapy (calcitonin, bisphosphonates) could stop the progressive osteolytic changes.

Aged↗

PubMed1999

[Chondromyxoid fibroma. Morphological variations, site, incidence, radiologic criteria and differential diagnosis].

Chondromyxoid fibroma is a rare benign bone tumor, accounting for less than 1% of all bone tumors. The peak age incidence is the second and third decade of life. Chondromyxoid fibrom occurs in the metaphyseal parts of the major tubular bones, predominantly of the lower extremity. Roentgenograms show, in most cases, a well-demarcated radiolucent lesion. The classic histological feature of a chondromyxoid fibroma is stellate or spindle-shaped cells arranged in lobules in a myxoid or chondroid background. Analysis of 40 chondromyxoid fibromas demonstrates the morphological variation of this tumor. Cases were examined for age distribution, localization, and radiological and histological features. In 85% we found the typical histomorphological pattern. Recurrence rate was 12.5%. In four cases the appearance was uncharacteristic and differentiation from other tumors such as chondroblastoma or chondrosarcoma was quite difficult. By adhering to strict histomorphological criteria, definite diagnosis of chondromyxoid fibroma can be made in most cases.

Adolescent↗

PubMed1999

[Ultra-small superparamagnetic iron oxide particles: the signal behavior and relaxation times of the bone marrow after repeated i.v. application in the pig model at 1.5 tesla].

PURPOSE: Evaluation of the influence of an iron-containing MR contrast agent on the signal behaviour and the relaxation time of the bone marrow at 1.5 tesla after repeated doses. ANIMALS AND METHODS: 14 pigs received i.v. on days 1, 9, and 15 ultra-small (core diameter 6-8 nm) superparamagnetic iron oxide particles at doses of 20 (low dose = LD) or 200 mumol/kg body weight (high dose = HD). RESULTS: Following the first administration a dose-independent reduction in the bone-marrow signal intensity in the T2-weighted gradient-echo sequence (FFE) was observed together with a reduction in the T1 and T2 relaxation times. Following the second application there were no further signal-reductions in the HD-group; in contrast, there was a signal reduction in the LD-group, made possible by a signal recovery in the meantime. On the other hand, the relaxation times T1 and T2 were shortened after each administration of contrast medium. CONCLUSION: Nano-SIPS result at both doses in a signal reduction in the bone marrow. Only in the LD-group may repeated examinations with new contrast agent offer diagnostically sufficient images. Relaxometry shows a shortening of T1 as well as T2. This effect could be summed up after repeated doses. Almost no iron remained in the medullary space three weeks after i.v. administration of the contrast agent, which suggests mobilization and metabolization.

Animals↗

PubMed1999

The Gorham-Stout syndrome (Gorham's massive osteolysis). A report of six cases with histopathological findings.

The Gorham-Stout Syndrome (Gorham's massive osteolysis) is a rare condition in which spontaneous, progressive resorption of bone occurs. The aetiology is poorly understood. We report six cases of the condition and present evidence that osteolysis is due to an increased number of stimulated osteoclasts. This suggests that early potent antiresorptive therapy such as with calcitonin or bisphosphonates may prevent local progressive osteolysis.

Adult↗

PubMed1999

Severe osteoporosis in familial Hajdu-Cheney syndrome: progression of acro-osteolysis and osteoporosis during long-term follow-up.

Hajdu-Cheney syndrome is an autosomal dominant inherited osteodysplastic bone disease with the hallmarks of acro-osteolysis, skull deformations, and generalized osteoporosis. Very few patients have been followed long-term with respect to the prognosis of acro-osteolysis and osteoporosis. Here we describe a 39-year-old woman and her 19-year-old daughter who are both affected with the Hajdu-Cheney syndrome. Skeletal lesions were followed in the mother between the ages of 22 and 39 years. The acro-osteolytic lesions progressed markedly and caused shortening of several fingers; some end phalanges had completely disappeared. Severe spinal osteoporosis with serial vertebral fractures was found at the age of 22 years. New vertebral fractures developed until the age of 33 years, but did not progress afterward. High turnover osteoporosis was found in the bone histology of iliac crest biopsies performed at the ages of 22 and 34 years. Bone mineral content (BMC) was strikingly decreased at the age of 34 years (T score -5.1 SD) and did not significantly change during further follow-up. In the daughter, BMC failed to increase between the ages of 12 and 19 years and was also markedly decreased (T score -4.4 SD). This suggests that osteoporosis in Hajdu-Cheney syndrome is related to a low peak bone mass and a high bone turnover, leading to insufficient bone formation compared with the increased bone resorption.

Adult↗

PubMed1999

[A simplified procedure for mechanical testing of lumbar spinal fixation implants].

On the basis of the current ASTM and ISO standard proposals, a simplified test procedure for spinal fixation implants has been developed. It comprises static and dynamic tests aimed at evaluating the stiffness and strength of various different internal implants. Different methods of mounting the pedicle screws to the test device are shown to significantly affect the characteristic values and failure mechanisms of the implants. The feasibility of the procedure was investigated by comparing 7 different internal fixation implants. The reproducible results revealed general differences associated with the material, dimensions and design, which latter in particular correlated with the specific failure mechanisms. For longer-term in situ duration, testing of these implants should be expanded to include an analysis of wear and corrosion properties.

Biomechanical Phenomena↗

PubMed1999

Evaluation of neoadjuvant therapy response of osteogenic sarcoma using FDG PET.

UNLABELLED: According to the current treatment protocol of the Cooperative Osteosarcoma Study (COSS), monitoring preoperative chemotherapy response and estimating grade of tumor regression in patients with osteosarcoma is mandatory before surgical removal of the tumor, particularly if a limb salvage procedure is intended. In addition, response to neoadjuvant chemotherapy is considered as an important prognostic indicator. The aim of this prospective study was to assess the usefulness of 2-(18F) fluoro-2-deoxy-D-glucose (FDG) PET in the noninvasive evaluation of neoadjuvant chemotherapy response in osteosarcoma. METHODS: In 27 patients with osteosarcoma, we determined tumor-to-background ratios (TBRs) of FDG uptake with PET, before and after neoadjuvant chemotherapy according to COSS 86c or COSS 96 protocols, respectively. We compared changes in glucose metabolism of osteosarcomas with the histologic grade of regression in the resected specimen, according to Salzer-Kuntschik, discriminating responders (grades I-III; n = 17) and nonresponders (grades IV-VI; n = 10). RESULTS: The decrease of FDG uptake in osteosarcomas expressed as a ratio of posttherapeutic and pretherapeutic TBRs showed a close correlation to the amount of tumor necrosis induced by polychemotherapy (P < 0.001; Spearman). With a TBR ratio cutoff level of 0.6, all responders and 8 of 10 nonresponders could be identified by PET. In addition, lung metastases of osteosarcoma were detected with FDG PET in 4 patients. CONCLUSION: FDG PET provides a promising tool for noninvasive evaluation of neoadjuvant chemotherapy response in osteosarcoma. This could imply consequences for the choice of surgical strategy, because a limb salvage procedure cannot be recommended in patients nonresponsive to preoperative chemotherapy unless wide surgical margins can safely be achieved.

Adolescent↗

PubMed1999

Insulin-like growth factor 1 and 2 serum concentrations in dialysis patients with secondary hyperparathyroidism and adynamic bone disease.

BACKGROUND: Insulin-like growth factor-1 and -2 exert well characterized effects on bone metabolism via paracrine and endocrine pathways. However, the role of circulating levels of IGFs and their binding proteins (IGFBP) in renal bone disease is still controversial. PATIENTS AND METHODS: To investigate whether circulating IGFs play a role in the pathogenesis of different forms of renal bone disease, we performed a cross sectional study in 38 stable dialysis patients (32 hemodialysis, 6 peritoneal dialysis). Patients were selected for the type of bone disease according to biochemical bone markers and bone histology. 25 Patients had adynamic bone disease (ABD; defined by plasma iPTH < 1,5 fold the upper limit of normal). Thirteen patients had secondary hyperparathyroidism (sHPT; defined by plasma iPTH > 10 fold the upper limit of normal). Serological diagnosis was confirmed in a subgroup of patients by bone histology (12 patients with type IIa according to Delling, ABD; 9 patients with type IIIb according to Delling, sHPT). Patients with signs or symptoms of aluminum toxicity were excluded from the study. RESULTS: Serum IGF-1 and -2 concentrations were comparable in both groups and were within the reported normal range for an age matched healthy control population. They did not correlate with biochemical markers (iPTH, bAP, osteocalcin) or histological manifestations of renal bone disease. Furthermore, semiquantitative analysis of IGFBP-2 and -3 carried out in patients with bone biopsies did not correlate with biochemical markers or histological indices of renal bone disease. CONCLUSION: In conclusion, in contrast to previous reports, the present data do not confirm a correlation between serological or histological markers of renal osteodystrophy and circulating IGF-1 or -2 or IGFBP-2 and -3. This does not exclude that potential alterations of the local IGF system may play a role in the pathogenesis of uremic bone disease.

Chronic Kidney Disease-Mineral and Bone Disorder↗

PubMed1998

[Phosphate deficiency as a rare cause of osteomalacia--case report of several years of enteral feeding and antacid therapy].

HISTORY AND CLINICAL FINDINGS: Floor-of-the-mouth cancer had been diagnosed and surgically treated in a 55-year-old man 4 years before the latest admission. For the last 3 years he had been fed through a percutaneous endoscopic gastrostomy (PEG). Since then he had experienced reflux oesophagitis which was being treated with aluminium-containing antacids. He was hospitalized for the surgical treatment of bilateral fractures of the neck of the femur. A surgical biopsy revealed osteomalacia but no metastasis. INVESTIGATIONS: The serum phosphate level was significantly reduced (0.21 mmol/l) and there was no detectable phosphate excretion in the 24-hour urine. Serum calcium concentration was unremarkable, but there was hypercalciuria (34.4 mmol/d). Alkaline phosphate activity was significantly raised (393 U/l) and parathormone level reduced (7 ng/l). Vitamin D concentration was unremarkable. TREATMENT AND COURSE: The phosphate content in the parenteral feed was at first increased and additional phosphate was given by mouth. The calcium and phosphate levels slowly became normal only after medication had been changed from antacids to H2-blockers. CONCLUSIONS: In this case osteomalacia was caused not by vitamin D deficiency but by a lack of phosphate. The reduced intestinal phosphate absorption by the antacids only partially explains the pronounced clinical signs. If antacids are taken over long periods the phosphate balance should be carefully monitored to avoid osteomalacia.

Alkaline Phosphatase↗

PubMed1998

[Quantitative morphology of vertebral body cortical bone. Building block for noninvasive calculation of fracture threshold in osteoporosis].

The vertebral bodies consist of two main structures, trabecular and cortical bone. The histological changes within the spine, especially in cortical bone, leading to osteoporotic fractures remain, however, poorly understood. Therefore, the complete front column of the spine was removed in 26 autopsy cases without skeletal diseases and in 11 cases with proven osteoporosis. A sagittal segment prepared through the center of all vertebral bodies was undecalcified embedded in plastic, ground to a 1-mm-thick block and stained using a modification of the von Kossa method. The analysis included measurement of the mean cortical thickness of both ventral and dorsal shell (from C3 to L5). The qualitative investigation of the structure of the cortical ring completed the analysis. The skeletally intact specimens had high cortical thickness values in the cervical spine (285 +/- 22 microns), a decrease in the thoracic spine (244 +/- 14 microns) and an increase in the lumbar spine (290 +/- 15 microns). The mean thickness of the ventral shell is in general higher than the thickness of the dorsal shell. The cortical thickness of the spine showed no gender-specific differences (P = n.s.). There was a slight decrease in the cortical thickness with age; however, this decrease and the correlation of cortical thickness to age was only significant below vertebral body T8 (r = 0.225 to 0.574; Pr < 0.05 to Pr < 0.005). Most interestingly, osteoporosis is characterized by a significant decrease in cortical thickness throughout the whole spine. This decrease in cortical thickness was more marked in the dorsal shell (P < 0.05) than in the ventral shell (ventral from C3 to T6 (P < 0.05) below T6 (P = n.s.). We therefore conclude that in osteoporosis, biomechanical competence is affected by both trabecular bone loss and decrease of cortical thickness. This suggests that, in addition to trabecular bone measurements, the cortical thickness is of special interest for diagnostic radiological examinations (CT) to yield clues about the risk of vertebral fractures.

Adolescent↗

PubMed1998

[Biology of osteoclasts; their role in bone metastases].

Bone is a common site for metastasis of malignant tumors. These can be recognized radiologically as either lytic or sclerotic lesions since the tumor cells stimulate resident bone cells to cause excessive local resorption or new bone formation. The osteoclast, as the only cell being capable of resorbing bone, is of major importance for the homing of tumor cells in bone and progression of metastasis due to bone destruction. Thus, the improvement of our means of therapeutic intervention towards prevention of tumor progression and pathological fractures will depend on our better understanding of both the molecular basis of bone resorption and the cellbiology of the osteoclast. This article presents our current opinion of the molecular mechanisms of bone resorption by the osteoclast. After describing the morphological features of the osteoclast, aspects such as cell mobility, attachment, enzymes synthesis, transmembrane transport, osteoclast differentiation and function, as well as the protooncogenes c-src and c-cbl and their role in bone resorption are presented in detail.

Bone Neoplasms↗

PubMed1998

Heterogeneity of trabecular bone structure in the calcaneus using magnetic resonance imaging.

The purpose of this study was to quantify the heterogeneity in the trabecular bone structure in the calcaneus. Magnetic resonance (MR) images of the calcaneus were obtained in the sagittal plane at an in-plane resolution of 195 microns and a slice thickness of 1000 microns in 12 young normal subjects. Regions of interest (ROI) were selected to cover the calcaneus using a grid of square boxes (10 mm per side). A thresholding technique based on the regional intensity histogram was used to segment the images into trabecular bone and marrow phases and to calculate measures such as apparent trabecular bone area fraction, apparent trabecular spacing, apparent trabecular thickness and apparent trabecular number. Bone mineral density (BMD) of the calcaneus was assessed using dual-energy X-ray absorptiometry (DXA). Histological sections of three calcanei were also analyzed using transmission light illumination, and the results used to calibrate our computational software. For a relatively narrow inter-subject variation in posterior BMD, a significant inter-subject variation was seen in MRI-derived structural parameters. Furthermore, the spatial heterogeneity of the structural parameters in the posterior region was as high as 40%. Thus, the posterior tuberosity of the calcaneus, a typical site for BMD and single-point ultrasound assessments, can demonstrate significant regional variation in trabecular bone structure.

Absorptiometry, Photon↗

PubMed1998

Long-term results of the co-operative German-Austrian-Swiss osteosarcoma study group's protocol COSS-86 of intensive multidrug chemotherapy and surgery for osteosarcoma of the limbs.

BACKGROUND: In an effort to intensify osteosarcoma therapy, systemic ifosfamide was added pre- and postoperatively to an already aggressive three-drug regimen. In a subgroup of patients, loco-regional treatment intensification was attempted by using the intraarterial route to give cisplatin. PATIENTS AND METHODS: Patients < or = 40 years at diagnosis of a localised, de novo high-grade central extremity osteosarcoma were eligible for inclusion into study COSS-86 if registered within three weeks from biopsy. Doxorubicin, high-dose methotrexate, and cisplatin were given to all patients. Patients who fulfilled one or more of three defined high-risk criteria received early systemic treatment intensification by adding ifosfamide as the fourth agent. Preoperatively, these high-risk patients received cisplatin either intraarterially or intravenously. RESULTS: 171 eligible patients were entered, of which 128 were stratified into the high-risk group. When all 171 were analysed by intention-to-treat, actuarial overall and event-free survival rates at ten years were 72% and 66%, respectively. No benefit of intraarterial cisplatin application was detected. Cumulative treatment toxicity was considerable. CONCLUSIONS: In a multicenter setting, intensive treatment of osteosarcoma according to protocol COSS-86 led to long-term disease-free survival for two thirds of patients. We saw no benefit of using the intraarterial route to administer cisplatin.

Adolescent↗

PubMed1998

Normalization of mineral ion homeostasis by dietary means prevents hyperparathyroidism, rickets, and osteomalacia, but not alopecia in vitamin D receptor-ablated mice.

1,25-Dihydroxyvitamin D3 plays a major role in intestinal calcium transport. To determine what phenotypic abnormalities observed in vitamin D receptor (VDR)-ablated mice are secondary to impaired intestinal calcium absorption rather than receptor deficiency, mineral ion levels were normalized by dietary means. VDR-ablated mice and control littermates were fed a diet that has been shown to prevent secondary hyperparathyroidism in vitamin D-deficient rats. This diet normalized growth and random serum ionized calcium levels in the VDR-ablated mice. The correction of ionized calcium levels prevented the development of parathyroid hyperplasia and the increases in PTH messenger RNA synthesis and in serum PTH levels. VDR-ablated animals fed this diet did not develop rickets or osteomalacia. However, alopecia was still observed in the VDR-ablated mice with normal mineral ions, suggesting that the VDR is required for normal hair growth. This study demonstrates that normalization of mineral ion homeostasis can prevent the development of hyperparathyroidism, osteomalacia, and rickets in the absence of the genomic actions of 1,25-dihydroxyvitamin D3.

Alopecia↗

PubMed1998

[Diagnosis of bone tumors].

The correct diagnosis of bone tumors involves considerable methodological efforts. Because of the rarity of primary bone tumors Uehlinger initiated a centralisation in the form of bone tumor registries. A sufficient number of these registries exist in the German-speaking countries (for example, Münster, Madgeburg, Giessen, Freiburg, Basel, Wien). Our experience with the organisation of interdisciplinary collaboration, methodology and the value of special examination techniques (immunohistochemistry, DNA analysis, cytogenetics) are reported. Since 1975, 7,576 primary bone tumors have been recorded in the Hamburg Bone Tumor Registry. A total of 9,895 biopsy/resection specimens have been examined. Frozen section diagnosis in combination with imprint cytology can be performed as for other tumors. Routine techniques are paraffin embedding, if necessary following EDTA decalcification, and plastic embedding. By means of contact x-rays good insights can be gained into the extent of bone matrix formation or the osteolytic activity of bone tumors. These findings correlate well with the results of clinical imaging. In special cases DNA analysis and various immunohistological reactions can contribute substantially to a correct diagnosis. So far cytogenetics and molecular biology are of only limited use in routine diagnostics, apart from Ewing's sarcoma. In spite of sufficient experience of many registries there are still a number of inaccurately defined primary bone tumors with uncertain biology, for example low grade malignant osteosarcoma. A clear characterization of these tumors using new techniques is a task for the future.

Bone Neoplasms↗

PubMed1998

PTHrP and Bcl-2: essential regulatory molecules in chondrocyte differentiation and chondrogenic tumors.

Human chondrosarcomas (CS) are a frequent form of malignant bone tumors. The accurate distinction between benign solitary enchondroma and conventional CS of bones is a major diagnostic goal. Although the histological characteristics of chondrogenic tumors and the grading of CS (G1 to G3) have been defined by several authors, immunohistochemical markers for the different entities and grades are still missing and the mechanisms of tumorigenesis remain poorly understood. In addition to the emerging evidence that parathyroid hormone-related peptide (PTHrP) plays a critical role in endochondral bone formation we have recently reported that Bcl-2 lies downstream of PTHrP in the regulation of chondrocyte differentiation. To further characterize chondrogenic tumors and to determine whether PTHrP and the regulation of Bcl-2-expression is of relevance to tumorigenesis, we analyzed the expression of both PTHrP and Bcl-2 on a series of 23 cases of solitary enchondroma (9 cases) and primary CS (14 cases) using light and confocal microscopy. While all 9 enchondromas exhibited a detectable level of PTHrP-expression only, 2 showed low levels of immunoreactivity for Bcl-2. In sharp contrast, strong coexpression of Bcl-2 and PTHrP was found in 11 (composed of 3 CS G3, 7 CS G2, and one dedifferentiated CS) out of 14 CS, while the expression level of these proteins was below the detection limit in two CS G1 and one dedifferentiated CS. To verify this data 3 cases each of enchondroma, CS G2, and CS G3 respectively, were subjected to quantitative confocal analysis, after double labeling for PTHrP and Bcl-2. The results showed a significant increase in the expression of both PTHrP and Bcl-2, in malignant CS versus the benign enchondromas. Most interestingly, the levels of expression of both PTHrP and Bcl-2 correlated with the degree of malignancy of the chondrogenic tumors. These results therefore suggest that both PTHrP and Bcl-2 play a role in the tumorigenesis of chondrogenic tumors and further indicate that both proteins may participate in the same pathway regulating chondrocyte differentiation.

Adult↗

PubMed1998

[Cytogenetic changes in low grade central osteosarcomas].

Low grade central osteosarcomas are a group of rare bone neoplasms morphologically simulating benign bone tumors or tumor-like lesions (fibrous dysplasia, nonossifying fibroma, osteoblastoma, chondromyxoidfibroma or aneurysmal bone cyst). Because of the apparent bland histology they may be misinterpreted as benign lesions despite their primary low malignant behavior and late metastatic potential including the capability to transform into a highly malignant sarcoma. In contrast to high grade osteosarcomas cytogenetic studies of these entities are very rare. Karyotyping including FISH analysis with painting- and centromere-specific probes was done in 2 cases of low grade central osteosarcomas (fibrous dysplasia like type). One case was a primary lesion in the upper femur, the other was a recurrent lesion in the upper humerus. Additionally a static DNA cytometry using Feulgen stained imprints was carried out in both cases. In the first case clonal aberrations with a Robertsonian translocation between chromosomes #14 und #15, balanced translocations including chromosomes #5 and #21, #12 and #20, and a supernumary ring chromosome derived from chromosome #1 were detected in a near diploid karyotype. The second case displayed the development from a DNA-diploid to a DNA-peritetraploid lesion during a follow up of six years. Cytogenetic different marker chromosomes and again ring chromosomes were detected in a near tetraploid karyotype. Low grade central osteosarcomas of fibrous dysplasia like type may be characterized by chromosomal aberrations including ring chromosomes. Regarding the last feature these cytogenetic findings resemble those found in low grade parosteal osteosarcomas and other mesenchymal lesions of borderline behavior or low malignancy grade (for example dermatofibrosarcoma protuberans, low grade liposarcoma).

Adolescent↗